Traditionally, advanced electronic display systems have only been used for indoor applications or outdoor applications where the variation in temperature and/or amount of direct sunlight is limited. When these systems are moved outside, both temperature and sunlight become significant factors in the display's ability to produce an image and maintain an adequate operating temperature for the various components within the display.
Cold temperatures may be especially harmful to liquid crystal display (LCD) systems where the crystals can respond less quickly and in extreme cases can actually freeze. Heat is also harmful to many electronic displays as the electrical components which drive the display system may overheat and malfunction. In order to prevent damage to the display components in high or low temperatures, a number of heating and cooling systems have been proposed. Although some of these systems are able to adequately control the temperature of the display, many times these systems require large amounts of power.
Several issues become concerning when displays begin to draw large amounts of power. Obviously, energy concerns are always an issue, and consumers desire to keep energy consumption and corresponding energy costs at a minimum. Further, large power consumption can correspond to a spike in current draw and the risk of overloading a local circuit, most notably in the form of tripping a breaker or fuse. Often times the line voltages which are supplying these displays may fluctuate, either mild or large (‘brown outs’). A lowering of the line voltage typically results in an increased current draw by the display and subsequently an overload on the local circuit. Thus, there exists a need to develop a system which can maintain the best possible display performance while controlling the power consumption and preventing the overloading of a local circuit.